1. Technical Field of the Invention
The present invention relates to a method for controlling the drive of an actuator of an active vibration isolation support system comprising an elastic body receiving vibration from an engine, a liquid chamber having a wall of which at least a part is formed from the elastic body, a movable member for changing the capacity of the liquid chamber, and an actuator for driving the movable member by means of an electromagnetic force.
2. Discussion of Relevant Art
Such an active vibration isolation support system is known from Japanese Patent Application Laid-open No. 7-42783.
This active vibration isolation support system changes a spring constant by applying alternating current to an actuator so as to vibrate a movable member. The relationship between the phase and peak current value of the alternating current that sets the spring constant is stored as a map, and the phase and peak current value of the alternating current to be applied to the actuator are obtained from the map according to the rotational speed of the engine, thereby allowing the active vibration isolation support system to exhibit an effective vibration isolation function in various regions of the rotational speed of the engine.
However, this conventional system cannot always exhibit an effective vibration isolation function since there are variations among individual engines in the vibration magnitude and the vibration phase, and the influence of changes in the vibration characteristics accompanying long-term use of the engine cannot be taken into consideration.
The present invention has been achieved under the above-mentioned circumstances, and it is an object of the present invention to allow an active vibration isolation support system to exhibit an effective vibration isolation function in accordance with the vibration characteristics of individual engines.
In order to achieve the above-mentioned object, in accordance with a first aspect of the present invention, there is proposed a method for controlling the drive of an actuator of an active vibration isolation support system comprising an elastic body receiving vibration from an engine, a liquid chamber having a wall of which at least a part is formed from the elastic body, a movable member for changing the capacity of the liquid chamber, and an actuator for driving the movable member by means of an electromagnetic force, the method comprising the steps of estimating an engine vibration magnitude and an engine vibration phase by detecting crank pulses of the engine, and controlling the actuator based on the estimated engine vibration phase when the estimated engine vibration magnitude is equal to or greater than a predetermined value, and controlling the actuator based on a preset engine vibration phase when the estimated engine vibration magnitude is less than the predetermined value.
In accordance with this arrangement, the engine vibration magnitude and the engine vibration phase are estimated from crank pulses of the engine, and the actuator is controlled based on the estimated engine vibration phase when the estimated engine vibration is large. Therefore, an effective vibration isolation function can be exhibited by appropriately controlling the actuator without it being influenced by variations in the magnitude and phase of the vibration among individual engines or changes in the vibration characteristics accompanying long-term use of the engine. Furthermore, the actuator is controlled based on the preset engine vibration phase when the estimated engine vibration is small, even when it is difficult to estimate the engine vibration phase because the engine vibration is small. Therefore, an effective vibration isolation function can be exhibited by appropriately controlling the actuator.
Moreover, in accordance with a second aspect of the present invention, there is proposed a method for controlling the drive of an actuator of an active vibration isolation support system comprising an elastic body receiving vibration from an engine, a liquid chamber having a wall of which at least a part is formed from the elastic body, a movable member for changing the capacity of the liquid chamber, and an actuator for driving the movable member by means of an electromagnetic force, the method comprising estimating an engine vibration magnitude and an engine vibration phase by detecting crank pulses of the engine, and controlling the actuator based on the estimated engine vibration magnitude and the estimated engine vibration phase when the estimated engine vibration magnitude is equal to or greater than a predetermined value, and controlling the actuator based on the estimated engine vibration magnitude and a preset engine vibration phase when the estimated engine vibration magnitude is less than the predetermined value.
In accordance with this arrangement, the engine vibration magnitude and the engine vibration phase are estimated from crank pulses of the engine, and the actuator is controlled based on the estimated engine vibration magnitude and the estimated engine vibration phase when the estimated engine vibration is large. Therefore, an effective vibration isolation function can be exhibited by appropriately controlling the actuator without it being influenced by variations in the magnitude and phase of the vibration among individual engines or changes in the vibration characteristics accompanying long-term use of the engine. Furthermore, the actuator is controlled based on the estimated engine vibration magnitude and the preset engine vibration phase when the estimated engine vibration is small. Therefore, even when it is difficult to estimate the engine vibration phase because the engine vibration is small, an effective vibration isolation function can be exhibited by appropriately controlling the actuator.
The elastic body of the present invention corresponds to a first elastic body 14 of an embodiment, the liquid chamber of the present invention corresponds to a first liquid chamber 24 of the embodiment, and the engine vibration magnitude of the present invention corresponds to an amplitude at the position of an active vibration isolation support system M of the embodiment.
Modes for carrying out the present invention are explained below by reference to an embodiment of the present invention illustrated in the attached drawings.